This invention relates to a method and apparatus for continuous offset tuning of a frequency-stabilized gas laser over the spectral linewidth of the gas.
It is frequently necessary, or desirable, for general laboratory applications to offset a CO.sub.2 gas laser from the line center, but it then becomes a problem of stabilizing the frequency. The prior art teaches techniques for so stabilizing a gas laser that it seeks the center of an absorption line of a gas molecule, or for stabilizing on a few specific laser lines offset from the center using the Stark technique.
The present invention provides an improved technique for stabilizing frequency of a gas laser capable of continuous offset tuning over the spectral linewidth of the gas. That is an improvement over the prior art Stark technique which is restricted to a small number of laser lines, or other techniques that stabilize at the line center, in that the offset from line center can be chosen for every laser transition with the ability to stabilize at any spectral line with any desired offset from line center. The improved technique is applicable to several types of gas lasers such as, but not limited to, CO, CO.sub.2 and N.sub.2 O, with the same gas in the spectrophone.